Gun sights are used on firearms to aid in aiming the firearm. Properly trained gun owners (including military and law enforcement) will use the sights to aim the weapon. Given that a handgun may be used in a life threatening situations, the weapon's user has very little time to aim the weapon at a target. However proper aim is critical to minimize potential injury to bystanders and to ensure that the target threat is neutralized.
A standard handgun sight includes a single, raised front sight centered at the top, front surface of the gun barrel or gun slide. The front sight is a single raised projection. The rear sight is an elongate projection with a central notch at the rear of the gun. The central notch of the rear sight is centered on the barrel or slide of the gun. To aim the gun, the target is aligned with the front sight, when the front sight is aligned with the notch of the rear sight.
Additional difficulty is encountered in low or variable lighting conditions when the front and rear sights are more difficult to see. One widely adopted solution to this problem is to use tritium sights. The front and rear sights of the handgun are modified to include space for a clear vial visible to a user firing the weapon. The inside of this clear vial is a coating of phosphor or other gas that may be excited by radioactive emissions from the radioactive tritium gas. The resulting glow is visible to the user, allowing the sights to be used in lower light conditions (e.g. dark interiors or nighttime).
There are a number of known drawbacks to the use of tritium or other radioactive gasses in this application of use in a gun sight. Any radioactive compound will have a characteristic decay. Tritium has a half-life of 14 years, meaning that after 14 years half of the tritium will have decayed into helium. In addition, the phosphorescent coating also may be subject to degradation over time, could be subject to photo bleaching, or other factors which degrade its efficacy. A gun sight will begin to decay once manufactured. It is difficult to tell the age of the tritium, and used guns or older sights are difficult to evaluate. A user is faced with a continually degrading light source, which is not ideal. Ideally, the light source would be consistent, eliminating a variable during the stressful conditions of firearm use. In addition, these tritium gun sights are going to emit light at a single brightness.
The phosphorescent compounds currently used in gun sights emit at a variety of different wavelengths, allowing selection of different colors to be observed by a user. Human visual perception makes green and yellow preferred colors for use in this application. Commonly a first color is used on the front sight and a second color is used on two vials in the rear sight that flank the notch in the rear sight. This makes centering the front sight in the notch easier, and reduces the changes of misalignment of the front sight to the left or right side of the rear sights (rather than between the rear sights). In addition, the size of the phosphorescent windows can be varied between the front and rear sights to aid in alignment.
In addition to degradation of luminescent sights, installation of sights can also be a concern with this technology. Generally, the sights that are available in the standard manufactured weapon are not luminescent. When tritium sights are installed, generally vertical and horizontal adjustment are required to make sure that the current sights are useful for achieving true aim.
Horizontal adjustment requires that the old sights be removed from the guns and that the new rear sights are installed in a dove tail mounting and adjusted to ensure that the sight is properly centered such that the gun will aim true. The average shooter or consumer can't easily or carefully take off stock sights (or what are called “iron sights”) alone. Once a consumer obtains “Night Sights” the consumer generally will have the new sights installed by either a gun smith or other professional that owns a tool called a “Sight Pusher”. A sight pusher is a heavy metal handheld device that locks on to a slide (that has been removed from the handgun). A screw device on the sight pusher tool is used to push the old sight out of the dove tail mounting, removing the old sight from the slide of the gun. The new sights are then placed in the start of the dovetail and the sight pusher, using the same screw device, pushes the new sight in to place.
The device still must be horizontally adjusted to aim true. This generally requires that the gun owner takes the gun to a gun range (with the new sight mounted on the gun), and, with the aid of a sight pusher, move the rear sight left or right as needed. In some instances a professional at a gun range (or the gun owner) can use a brass punch and hammer to incrementally move the rear sight left or right to the desired location. This method can also be used to take off iron sights. However this is not an easy process and requires some skill to avoid damaging the firearm or the sight. Sight pushers cost can range from a low of about $50 dollars to over $200 dollars. Since most people don't own a sight pusher and are reluctant to use a brass punch and hammer on their new sights they usually bring their shot at targets from the range back to the gunsmith. Looking at the used targets coupled with the known distance (say 25 yards) it was shot at, a gunsmith can ballpark estimate about how far he needs to move the rear sights left and right to compensate for each shooters needs. Again, more time and energy being expended on the installation and set up of the new sights.
Vertical adjustment requires shaving the sights down. This is generally done by an experienced gunsmith and like horizontal adjustment requires specialized tooling. Alternatively, a gunsmith could install fluorescent vials in existing sights on a gun by drilling out stock sights and placing fluorescent vials in the bored holes.
One object of the disclosed embodiments is to provide a gun sight system that allows use at night using an improved technology.